In the processing of animals, particularly poultry, the animals are typically transported to and through various processing operations along a processing line. At least some of these processing operations are automated. The animals are suspended from shackles which are, in turn, coupled with a conveyor for transporting the animals relatively rapidly along the processing line. The shackles generally depend vertically from the conveyor so as to be substantially parallel with one another.
During processing of animal carcasses, it is sometimes necessary to raise or lower the processing line relative to other portions of the processing line. When it is necessary to raise the processing line, the conveyor slopes upwardly. A convex radius connects the previous lower portion of the conveyor with the upwardly sloping portion. As the shackles travel along this convex radius their relative orientation changes, such that they are no longer parallel to one another. More specifically, they are oriented angularly to one another along radial lines extending outwardly from a center point of the convex radius, such that the lower portions of the shackles, which are opposite the connections with the conveyor, spread apart. Because this change in orientation does not result in physical contact or interference between adjacent animals, it is generally not necessary to prevent it.
When it is necessary to lower the processing line, the conveyor slopes downwardly. A concave radius connects the previous higher portion with the downward sloping portion. As the shackles travel along this concave radius their relative orientation changes, such that they are no longer parallel to one another. More specifically, they are oriented angularly to one another along radial lines extending inwardly toward a center point of the concave radius, such that the lower portions of the shackles, which are opposite the connections with the conveyor, move closer together. This change in orientation can result in physical contact or interference between adjacent animals.
Additionally, even when traveling generally horizontally through the various processing operations, such as scalding and de-feathering operations, some resistance, or rearward force, may result which tends to push the animals backward and changes their orientation. This can cause a number of problems, including that the changed orientation may reduce the efficacy of the processing operations. For example, when moving through a scalder, the animals may, if not held in the correct orientation, float as they move through the scalder, leading to inefficient and incomplete scalding. When moving through a picker, animal carcasses that are allowed to move freely in a rearward direction may ride up over the top of the machine, causing obstructions in the processing line. When moving through a hock cutter, if the animal carcasses are not held in proper orientation, the legs of the animal may be cut unevenly. Further, many plants use rehangers during movement of animal carcasses from a picking line to an eviscerating line. During rehanging, the animals are moved, by automated processes, from a picking shackle to an eviscerating shackle. This transfer requires correct orientation of the animal carcass. Thus, a number of problems may arise from improper orientation of animal carcasses along a processing line.
One solution to the last two problems is to incorporate a pivot mechanism into each shackle and to attach a chain or other linkage extending between a point on the shackle which is below the pivot mechanism and a point on an adjacent shackle which is above its pivot mechanism. In this manner, when the shackle travels along the concave radius, the pivot mechanism allows the shackle to pivot about the pivot mechanism, and thereby allows the change in orientation. When the shackle travels along the convex radius, or when the shackle travels horizontally and the animal experiences resistance, the chain prevents the shackle from pivoting, or from pivoting beyond a particular amount, about the pivot mechanism, and thereby controls the change in orientation.
Unfortunately, the prior art pivot mechanism is prone to failure and disconnection. When this occurs, the shackle remains connected to the conveyor by the chain or other linkage. As a result, the improperly suspended and positioned shackle impedes or otherwise interferes with the processing operations, and can damage the processing apparatuses. Furthermore, removing or repairing the shackle takes time, during which the processing operations must be stopped. In addition, use of a drag-back chain to prevent unwanted backwards movement of an animal carcass results in the coupling of two or more shackles, such that a problem with a single shackle and animal carcass affects multiple shackles.